Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...
This protection circuit was obtained in a 1969 Electronic Design. The SCR can be the current...
This circuit was found on an old EDN and can be used as a shield. Optical couplers are from the...